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From: Max Filippov <jcmvbkbc@gmail.com>
To: Guenter Roeck <linux@roeck-us.net>
Cc: David Laight <David.Laight@aculab.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Masahiro Yamada <masahiroy@kernel.org>,
	"linux-xtensa@linux-xtensa.org" <linux-xtensa@linux-xtensa.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Chris Zankel <chris@zankel.net>
Subject: Re: [PATCH] xtensa: Increase size of gcc stack frame check
Date: Tue, 14 Sep 2021 00:04:56 -0700	[thread overview]
Message-ID: <CAMo8BfLOhr8Gw9RbSM_pVhgokDcBZ3PgwQAG6sCxDBAm_rMy7Q@mail.gmail.com> (raw)
In-Reply-To: <46f59bf8-f243-b65c-07b3-8ecbf7b410fa@roeck-us.net>

On Mon, Sep 13, 2021 at 9:11 AM Guenter Roeck <linux@roeck-us.net> wrote:
> The functions I checked typically have pretty large local data
> (like, more than 700-800 bytes). The errors are only observed
> with xtensa:allmodconfig test builds. While it may be arguable
> if those functions really need that much data on the stack, it
> is unreasonable to assume that all those errors (again, more
> than 50) are ever going to get fixed, especially since the errors
> are only seen with xtensa and not with any other architecture

That's not what I observe. If I build allmodconfig on v5.15-rc1
for arm with gcc-8.3 I get 69 of them.

> (including parisc; setting a stack limit of 1024 works just fine
> with that architecture, at least with gcc 11.x). So the realistic

This comparison is a bit biased because allmodconfig on xtensa
enables KASAN which is not supported by the parisc. Disabling
KASAN roughly halves the size of stack frames for a few
instances that I've checked.

-- 
Thanks.
-- Max

  reply	other threads:[~2021-09-14  7:05 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-12  2:52 [PATCH] xtensa: Increase size of gcc stack frame check Guenter Roeck
2021-09-12  3:05 ` Max Filippov
2021-09-12  4:02   ` Guenter Roeck
2021-09-12  5:16     ` Max Filippov
2021-09-13 15:57 ` David Laight
2021-09-13 16:11   ` Guenter Roeck
2021-09-14  7:04     ` Max Filippov [this message]
2021-09-14 14:02       ` Guenter Roeck
2021-09-14 17:24         ` Max Filippov

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